class U(object):
    def __init__(self,name,age):
        self.__name=name
        self.__age=age

    #静态方法
    @staticmethod
    def is_void():
        return  "this is web"

    #元数据
    @property
    def age(self):
        return  self.__age

    #类方法
    @classmethod
    def info(cls):
        return 'class action'